We study a new type of securitization that deals with banks' processing time, mortgage-receivable-backed securities (MRBSs) issued by real estate developers. Unlike traditional mortgage-backed securities (MBSs), the major risk of underlying assets of MRBSs is payment delay instead of default and prepayment. Using unique loan-level data, we estimate proportional hazard models and detect factors that affect the risk of underlying assets of MRBSs, including bank characteristics, property-loan-household characteristics, local market conditions, and macroeconomic conditions. Especially, we find that the effects of house prices and loan-to-value ratios on MRBS risk are the opposite of those on traditional MBS risk. Based on the estimates, we simulate cash flows of an underlying-asset pool and analyze the shortfall risk of the corresponding security tranches. We find that the securitization process imposes a natural adverse selection on the underlying assets.